Engine/Transmission (1998.5 - 2002) 50K Gearbox Lube Report

[Shelby Griggs]

Thought I would share observations on my 50K gearbox lube change experience.



Drained and re filled the front and rear axles with Amsoil 75-90, replaced the six speed lube with OEM from mother DC and put Amsoil ATF in the transfer case.



I had previously replaced the rear axle fluid with the Amsoil at 12K.



The entire transmission was replaced at 26K, I assume including new fluid.



The factory fill on the front axle still looked very good at 50K



The transmission looked pretty good at roughly 25K on the factory fill oil. Quit a lot of grit in the bottom, both magnetic and non magnetic.



The ATF out of the transfer case was much dirtier than I would have thought, unless then installed something other than a red ATF at the factory.



The rear axle was ugly. Not sure why, about 38K on the Amsoil in there. I was expecting to still see it blue, but no joy there. At around 25K I had a rear axle seal go out and the dealer fixed under warranty. I am wondering now if maybe they replaced my Amsoil??? They claim they did not replace or add any fluid and none was listed on the RO.



I filled all boxes to the bottom of the fill hole. Now I will hope no leaks show up. I can't see it hurting, but there have been mixed reports of this causing seal failures, time will tell. BTW, the front axle was essentially at the bottom of the hole, this after 50K of periodically puking out the vent tube.



If my rear axle is typical, then I highly recommend something less than 50K as the life cycle on the oil.



Shelby

 

[Steve Campbell]

Less than 50,000.....yes!!!

I agree Shelby. With the weather, temp changes, towing, dusty roads, etc..... I have put my transfer case and rear diff on 25,000 mile intervals. Front diff seems to be able to go twice as far as the rear. I have changed the trans (NV4500) oil twice in 60,000.

 

[Sled Puller]

Shelby,

I change all my lubes at least once a year because of the weather around here.

But I did run my front 2 years and 70,000 miles on the Series 2000 75-90. It was still very blue when I drained it.

38,000 is no miles on that lube, makes you wonder if they did change it. There was NO blue left?



Sometimes the axle tubes draw moisture and will discolor the oil, but color alone does not determine if the oil is still doing its job.



Amsoil does not cause leaks, I can prove it. Do a search on here, and see how many threads come up with guys complainng about leaks on brand new trucks with factory fills.



Evidently, our seals are substandard.



I have had Amsoil in for 100,000. No leaks, except what I have broken sled pulling.

Thanks for the report.

 

[John Berger]

I agree about Amsoil not causing leaks. I went 39K in my rear-end with the Series 2000 75W-90. It still had some blue left in it, but not much. I sent a sample to Blackstone for analysis and the report was good. They recommended that I not run any more miles than I had, so I went to the Series 2000 75W-140 and I will change it every 30K. If I tow more than I expect, I may drop it to 25K intervals.

 

[Shelby Griggs]

Guys,



I wasn't implying the Amsoil would cause leaks, however filling to the bottom of the fill hole might, that was my point. The book says 10. 1 pints, and five quarts brings just to the bottom of the plug on the rear axle. It would be more like 8 pints if I left down where the book says at 3/4" below the plug.



Gene, there was no blue at all, murky brown / gray, and also looked like it could of had some water. I have not been in any water over a few inches deep, so if it was water it would have had to enter from spray or splash through the vent tube or a seal, or condensation.



Just looked in the owners manual and Dodge recommends 15K intervals on the rear axle (schedule B) and 45K intervals on the transfer case for A and B, the axles are not listed in Schedule A. I venture to say that the majority of us should be on schedule B. It would appear that the rear axle does work the lube pretty good.



Shelby

 

[Sled Puller]

Originally posted by Shelby Griggs

Guys,



I wasn't implying the Amsoil would cause leaks, however filling to the bottom of the fill hole might, that was my point. The book says 10. 1 pints, and five quarts brings just to the bottom of the plug on the rear axle. It would be more like 8 pints if I left down where the book says at 3/4" below the plug.

Shelby

I get you now, I doubt overfilling with a non-foaming oil would cause leaks, should be room in the axle tubes anyway.

The Mag-Hytec covers run extra high.



If it looked like that, I have to believe contamination.

 

[John Berger]

I'm running about 7. 5 quarts in my Dana 80 with the Mag-Hytec.

 

[Joseph Donnelly]

I change the transfer case ATF with Chevron Dexron 3 from Costco every 15,000 miles. I strongly recommend frequent changing of the transfer case lube. It is not very tolerant of contamination or lube breakdown.



I have had seal leakage in the diff when using a synthetic lube. I don't *know* the cause, but I went to premium petro LE607 in the hopes that I won't oil down the brake shoes again. I generally recommend 30,000 mile change intervals for the diffs and transmission. The diff seals are the same basic part that Dana has used for about 40 years. I feel that too much endplay on the axle bearings can contribute to seal leakage. the service manual specified tightening the nut to 120 ft lb and backing off 1/8 turn.



Gene aka Sled Puller is a wholesale distributor for Amsoil (vendor).

 

[Steve Campbell]

Joeseph Donnelly quoted the service manual...

"the service manual specified tightening the nut to 120 ft lb and backing off 1/8 turn. " With the Nylock nut, (which I love-best bearing play set-up I have seen) I just tighten it up to the 120, spin the assembly, back off 1/8 or more to achieve "play" and then tighten until the "play" is "just barely gone. "

 

[jwinnie]

"the service manual specified tightening the nut to 120 ft lb and backing off 1/8 turn. " With the Nylock nut, (which I love-best bearing play set-up I have seen) I just tighten it up to the 120, spin the assembly, back off 1/8 or more to achieve "play" and then tighten until the "play" is "just barely gone. "

You do this as a routine service??

 

[Joseph Donnelly]

No, just check once in a while. After the bearings, etc. break in, setting endplay right should not need to be re-done for a long time.